The present invention relates to semiconductor devices, and, in particular, relates to substrates upon which semiconductor devices are built, and, in greater particularity, relates to high Tc superconducting devices.
The edge-defined, film-fed crystal growth technique is a process used to produce thin ribbons of crystalline material and in the past has been used to produce objects of varying shapes including ribbons of sapphire. This process in the past has not been used to produce a bi-crystals of sapphire which could be used for semiconductor devices using the Josephson junction weak link. The article titled, "Edge-Defined, Film-Fed Crystal Growth" by Chalmers, Journal of Crystal Growth 13/14, (1972) 84-87 is incorporated by reference.
The following U.S. Pat. Nos. 3,650,703; 3,868,228; 3,915,656; 3,915,662; 3,953,174 and 4,028,059 are incorporated by reference as to the teaching of growing ribbons of sapphire with the above technique.
The use of bi-crystals for the use of making Josephson junctions has been reported and, in particular, a Josephson junction device may be put on a bi-crystal of SrTiO.sub.3. The article titled, "Thin film Bi.sub.2 Sr.sub.2 CaCu.sub.2 O.sub.8+x Josephson junctions and direct current superconducting quantum interference devices on (001) SrTiO.sub.3 bi-crystals," by T. Amrein et al., Appl. Phys. Lett. 63 (14) 1993, is incorporated by reference.
Thus, there exists a need for a suitable substrate for making high Tc superconducting devices such as a Josephson junction.